From a6c4b29a184ce7708819f4706877eedcd99a30f5 Mon Sep 17 00:00:00 2001
From: Lauri Kasanen <cand@gmx.com>
Date: Mon, 16 Mar 2015 11:07:00 +0000
Subject: Detect XRender support

git-svn-id: file:///fltk/svn/fltk/branches/branch-1.3@10622 ea41ed52-d2ee-0310-a9c1-e6b18d33e121
---
 FL/x.H       |  1 +
 configh.in   |  8 ++++++++
 configure.in | 10 ++++++++++
 src/Fl_x.cxx | 16 ++++++++++++++++
 4 files changed, 35 insertions(+)

diff --git a/FL/x.H b/FL/x.H
index b4fe5fa05..f1f23f918 100644
--- a/FL/x.H
+++ b/FL/x.H
@@ -161,6 +161,7 @@ public:
   static void x(Fl_Window* wi, int X) {wi->x(X);}
   static void y(Fl_Window* wi, int Y) {wi->y(Y);}
   static int ewmh_supported();
+  static int xrender_supported();
   static void activate_window(Window w);
 };
 
diff --git a/configh.in b/configh.in
index 49add67f8..39b3f2560 100644
--- a/configh.in
+++ b/configh.in
@@ -123,6 +123,14 @@
 
 #define HAVE_XCURSOR 0
 
+/*
+ * HAVE_XRENDER:
+ *
+ * Do we have the X render library?
+ */
+
+#define HAVE_XRENDER 0
+
 /*
  * __APPLE_QUARTZ__:
  *
diff --git a/configure.in b/configure.in
index f74b3670e..70a5a55fc 100644
--- a/configure.in
+++ b/configure.in
@@ -1018,6 +1018,16 @@ case $host_os_gui in
 		LIBS="-lXcursor $LIBS")
 	fi
 
+	dnl Check for the Xrender library unless disabled...
+        AC_ARG_ENABLE(xrender, [  --enable-xrender        turn on Xrender support [[default=yes]]])
+
+	if test x$enable_xrender != xno; then
+	    AC_CHECK_HEADER(X11/extensions/Xrender.h, AC_DEFINE(HAVE_XRENDER),,
+	        [#include <X11/Xlib.h>])
+	    AC_CHECK_LIB(Xrender, XRenderQueryVersion,
+		LIBS="-lXrender $LIBS")
+	fi
+
 	dnl Check for overlay visuals...
 	AC_PATH_PROG(XPROP, xprop)
 	AC_CACHE_CHECK(for X overlay visuals, ac_cv_have_overlay,
diff --git a/src/Fl_x.cxx b/src/Fl_x.cxx
index 772acae28..8ca25201e 100644
--- a/src/Fl_x.cxx
+++ b/src/Fl_x.cxx
@@ -69,6 +69,9 @@ static bool have_xfixes = false;
 #  if HAVE_XCURSOR
 #    include <X11/Xcursor/Xcursor.h>
 #  endif
+#  if HAVE_XRENDER
+#    include <X11/extensions/Xrender.h>
+#  endif
 static Fl_Xlib_Graphics_Driver fl_xlib_driver;
 static Fl_Display_Device fl_xlib_display(&fl_xlib_driver);
 Fl_Display_Device *Fl_Display_Device::_display = &fl_xlib_display;// the platform display
@@ -2230,6 +2233,19 @@ int Fl_X::ewmh_supported() {
   return result;
 }
 
+int Fl_X::xrender_supported() {
+  static int result = -1;
+
+  if (result == -1) {
+    fl_open_display();
+
+    int nop1, nop2;
+    result = XRenderQueryExtension(fl_display, &nop1, &nop2);
+  }
+
+  return result;
+}
+
 extern Fl_Window *fl_xfocus;
 
 void Fl_X::activate_window(Window w) {
-- 
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